Envelope for a laminar structure providing adaptive thermal insulation

Abstract

The present invention relates to an envelope ( 20 ) for a laminar structure providing adaptive thermal insulation, the envelope ( 20 ) enclosing at least one cavity ( 16 ) having included therein a gas generating agent ( 18 ) having an unactivated configuration and an activated configuration, the gas generating agent ( 18 ) being adapted to change from the unactivated configuration to the activated configuration, such as to increase a gas pressure inside the cavity ( 16 ), in response to an increase in temperature in the cavity ( 16 ), the envelope ( 20 ) being configured such that a volume of the envelope ( 20 ) increases in response to the increase in gas pressure inside the cavity ( 16 ), wherein the envelope ( 20 ) is made of a polymer composite material ( 8 ), the polymer composite material ( 8 ) including a fluid tight layer which is covered by a reinforcing layer comprising a polymer material, the rein-forcing layer being configured to limit formation of wrinkles in the fluid tight layer ( 8 b ) when subjecting the envelope ( 20 ) to one, or a plurality of activation/deactivation cycles.

The invention claimed is: 
     
       1. Envelope for a laminar structure providing adaptive thermal insulation, the envelope enclosing at least one cavity having included therein a gas generating agent having an unactivated configuration and an activated configuration,
 the gas generating agent being adapted to change from the unactivated configuration to the activated configuration, such as to increase a gas pressure inside the cavity, in response to an increase in temperature in the cavity, 
 the envelope being configured such that a volume of the envelope increases in response to the increase in gas pressure inside the cavity, 
 wherein the envelope is made of a polymer composite material, the polymer composite material including a fluid tight layer which is covered by a reinforcing layer comprising a polymer material, the reinforcing layer being configured to limit formation of wrinkles in the fluid tight layer when subjecting the envelope to one, or a plurality of, activation/deactivation cycles. 
 
     
     
       2. Envelope according to  claim 1 , comprising a porous layer, in particular an expanded PTFE layer, having a thickness between 30 and 400 μm, in particular between 70 and 250 μm. 
     
     
       3. Envelope according to  claim 1 , wherein the reinforcing layer is bonded to the fluid tight layer by a PU resin or by other thermoplastic material, e.g. FEP or PFA. 
     
     
       4. Envelope according to  claim 1 , wherein the reinforcing layer is configured to provide for additional thermal protection. 
     
     
       5. Envelope according to  claim 1 , wherein the reinforcing layer comprises a porous polymer material. 
     
     
       6. Envelope according to  claim 5 , wherein the porous polymer material has a density of 0.2 to 1 g/cm 3 . 
     
     
       7. Envelope according to  claim 5 , wherein the porous polymer material comprises an expanded fluoropolymer material. 
     
     
       8. Envelope according to  claim 7 , wherein the expanded fluoropolymer material includes expanded PTFE or is expanded PTFE. 
     
     
       9. Envelope according to  claim 1 , wherein the reinforcing layer has a composite structure including a porous polymer layer ( 8   e ) and at least one additional polymer material in contact with the porous polymer layer at least partially penetrating pores formed in the porous polymer layer. 
     
     
       10. Envelope according to  claim 9 , wherein the additional polymer material penetrates pores of the porous layer up to a penetration depth between 10 and 50 μm. 
     
     
       11. Envelope according to  claim 9 , wherein the additional polymer material forms an essentially homogeneous polymer layer at least on the side of the porous polymer layer facing towards the fluid tight layer. 
     
     
       12. Envelope according to  claim 9 , wherein the reinforcing layer is bonded to the fluid tight layer by the additional polymer material. 
     
     
       13. Envelope according to  claim 1 , wherein the envelope is made of a metal/polymers composite material including a fluid tight layer of metallic material. 
     
     
       14. Envelope according to  claim 13 , wherein the metallic material is Al or an Al based alloy. 
     
     
       15. Laminar structure providing adaptive thermal insulation, comprising
 a first layer, 
 a second layer, 
 at least one envelope according to  claim 1 , the envelope provided in between the first layer and the second layer, 
 the first layer, the second layer and the cavity being arranged such that a distance between the first layer and the second layer increases in response to the increase in gas pressure inside the cavity. 
 
     
     
       16. Fabric with a composite structure, the composite structure comprising a laminar structure providing adaptive thermal insulation or an envelope for a laminar structure providing adaptive thermal insulation according to  claim 15 .